Laminated glass is safety glass which, even when broken by impact from the outside, shatters into few flying glass fragments. For this reason, laminated glass is widely used for applications such as cars, railcars, aircrafts, boats, ships, buildings, and the like. The laminated glass is produced by sandwiching an interlayer film for laminated glass between a pair of glass plates. Such laminated glass used for openings of vehicles or buildings are required to have high heat-shielding properties.
Infrared rays having a wavelength of 780 nm or longer, which is longer than a wavelength of visible light, have a small amount of energy compared to ultraviolet rays. The infrared rays, however, have a large thermal effect, and are emitted as heat when absorbed by a substance. For this reason, the infrared rays are commonly referred to as heat rays. Laminated glass is therefore required to sufficiently shield infrared rays so as to have better heat-shielding properties.
The following Patent Document 1 discloses an interlayer film containing tin-doped indium oxide particles (ITO particles) or antimony-doped tin oxide particles (ATO particles) as an interlayer film that effectively blocks the infrared rays (heat rays).
The following Patent Document 2 discloses an interlayer film containing a near-infrared absorbing coloring matter, an ultraviolet absorber having a maximum absorption wavelength in the wavelength range of 250 to 400 nm, and an ethylene-vinyl acetate copolymer. Examples of the near-infrared absorbing coloring matter include phthalocyanine compounds, naphthalocyanine compounds, aminium salt compounds, and anthraquinone compounds.